Food and Body Shaming does not work.
I see this nearly every day in the United States Army. Body shaming is the norm in many parts of the military. To the military, your weight is purely a measure of your lack of discipline. This approach is not helpful and shows a genuine lack of understanding of the disease process in obesity. Obesity is a disease and is not merely a lack of willpower. We need to change how we look at folks who have become obese and more supportive and less blaming.
The bottom line: You did not need to make people feel bad about themselves to help them lose weight. You will do better if you show compassion and concern for their health.